Abstract: A method of producing cementitious mixtures containing fly ash as one of the cementitious components, under air entrainment conditions. The method involves forming a mixture comprising water, cement, fly ash, optionally other cementitious materials, aggregate, conventional chemical admixtures, and an air entrainment agent and agitating the mixture to entrain air therein. Additionally, at least one sacrificial agent is also included in the mixture. The sacrificial agent is a material or mixture of materials that is not required to act as an air entrainment agent but interacts preferentially with components of the fly ash that otherwise neutralize, repress or depress the activity of the air entrainment agent. The invention includes cementitious mixtures and hardened concretes resulting from the method and fly ash treated with sacrificial agent, or air entrainment agent/sacrificial agent combinations, and processes for selecting suitable sacrificial agents.

Abstract: A process of producing an aqueous solution of a sulfonated melamine-formaldehyde resin. The process comprises condensing melamine and formaldehyde or a precursor of formaldehyde (e.g. paraformaldehyde) in an aqueous mixture having a pH in the range of 8-10 to form a reaction mixture containing a condensation product of melamine and formaldehyde. The condensation product is then reacted in an aqueous mixture having a pH of 8-10, preferably 8-9, with a sulfonating agent to produce a mixture containing a sulfonated condensation product. Finally, polymerizing the said sulfonated condensation product in an aqueous mixture having a pH of 5-7 to form a resin solution. In the process, at least one of the sulfonation step and the polymerizing step is carried out under superatmospheric pressure (generally 5 to 70 p.s.i.) and at an elevated temperature of, in the case of the sulfonating step, 100.degree.-130.degree. C. for a time of 1 to 5 hours or of, in the case of the polymerizing step, 105-150.degree. C.

Abstract: The invention relates to basic polynucleate aluminum hydroxy silicate sulfate compounds and to a process for their preparation. The process involves first mixing an alkali metal silicate and an alkali metal aluminate solution and optionally a third component under continuous stirring to form an alkaline intermediate mixture and slowly adding the resulting alkaline intermediate mixture to an acidic aluminum sulfate solution under high shear mixing conditions. Compared to processes of the prior art, the present invention leads directly to solution products having higher Al.sub.2 O.sub.3 concentrations. Moreover, the products prepared through this invention exhibit enhanced stability over time, and improved performance in flocculation-coagulation application.

Abstract: A polynucleate aluminum hydroxy silicate-sulphate compound (PASS) having the following average composition:Al.sub.A (OH).sub.B (SO.sub.4).sub.C (SiO.sub.X).sub.D (H.sub.2 O).sub.EwhereinA is 1.0;B ranges from 0.75 to 2.0;C ranges from 0.30 to 1.12;D ranges from 0.005 to 0.1;X is greater than 2.0 but less than or equal to 4.0 such that 3=B+2C+2D (X-2);E is larger than 4 when the product is in aqueous form. The compound is useful for water treatment and other applications where an aluminum hydroxide gel system is required. The compound, in aqueous solution, has a long storage life.

Abstract: The specification discloses a method of stabilizing aqueous alkali metal aluminate solutions against precipitation of solids and/or the development of a cloudy appearance over a period of standing. The method comprises dissolving hydrated alumina and an alkali metal hydroxide in an aqueous medium in an amount sufficient to produce an aqueous solution containing at least 30% by weight of dissolved solids. The dissolved solids are then reacted in the presence of at least 0.02% by weight of an oligomeric or monomeric surfactant containing groups capable of bonding chemically to the aluminate thus produced. The resulting aluminate solution is found to be stable for a period of several months at least, and thus has a long shelf life making it attractive for use in a variety of industries.

Abstract: Electroless deposition of tin-nickel alloys is carried out using a plating solution containing a tin salt, a nickel salt and thiourea. The solution is particularly useful for spray or immersion plating of bronze Fourdrinier screens.